近年來，由於不斷電系統(Uninterruptible Power System)被廣泛應用於工業上，交流–交流背接型轉換器的議題也備受重視，而三階中性點箝位轉換器與二階轉換器相比，在相同的直流鏈電壓條件下開關元件的跨壓只有二階轉換器的一半，三階中性點箝位轉換器可輸出3種電壓等級，故能有效提高輸出品質，故此篇論文就針對背接型三階中性點箝位轉換器之架構去作探討。

　　背接型三階中性點箝位轉換器使用零序注入的技術去提高直流鏈電壓的利用率，考慮到市電非理想情況，轉換器交流—交流可能會操作於非同步的狀況，使得相同零序注入的效果受到影響，進而導致轉換器操作於過調節的情況發生。因此透過額外的直流鏈電壓與虛功電流去補償過調變的狀況，此外中性點電位的平衡也是考量之一。

　　另外，假設系統有第四線存在時，轉換器不同的共模電壓可能導致漏電流產生，為了抑制漏電流的產生，提出了邊緣對齊脈衝寬度調變技術可以有效的抑制漏電流的產生。最後實驗結果會在後面的章節作呈現以驗證所提出之方法是否有效。

　　In recent years, uninterrupted power supply systems are widely applied in the industry. The issue of AC-AC back to back converters is also highly attention. When the same dc bus voltage condition, the three-level neutral point clamp converter has the half switch cross voltage compare with two level converter and a three-level neutral point clamp converter can output three different level voltage so the output performance is better than two level converter. This thesis is focused on three-level back to back neutral point clamped converters.

　　Back to back NPC converter use zero sequence injection technique to enhance DC-bus utilization. Considering the non-ideal grid voltage, AC voltages on both ends are asynchronous, which affects the effect of the common zero-sequence injection. So we proposed additional DC bus voltage and reactive current to compensation over-modulation. Besides, the neutral point balance is one issue we consider.

　　Besides that, assume that the fourth wire exists in the system, the different common-mode voltages between rectifier and inverter may cause the circulating current. In order to suppress the circulating current, we proposed the Edge-alignment PWM technique to effectively suppress the generation of the circulating current. The laboratory test result is shown behind, then verify the proposed technique.

誌謝--------------------------------------------------------I
摘要-------------------------------------------------------II
Abstract--------------------------------------------------III
目錄-------------------------------------------------------IV
圖目錄-----------------------------------------------------VI
表目錄------------------------------------------------------X
第一章 緒論-------------------------------------------------1
1.1簡介-----------------------------------------------------1
1.2研究動機-------------------------------------------------2
1.3論文大綱-------------------------------------------------3
第二章 文獻回顧---------------------------------------------4
2.1 三階中性點箝位轉換器------------------------------------4
2.2 脈衝寬度調變法------------------------------------------6
2.3 三階空間向量調變法--------------------------------------8
2.4 三階轉換器電容中性點控制-------------------------------10
第三章 操作原理--------------------------------------------13
3.1 簡介---------------------------------------------------13
3.2 共模電壓與漏電流之關係---------------------------------14
3.3 權重控制策略-------------------------------------------16
3.3.1線性調變範圍限制--------------------------------------16
3.3.2相同零序注入與調節指數之關係--------------------------18
3.3.3權重控制之自由度--------------------------------------20
3.3.4直流鏈電壓與虛功電流權重控制--------------------------23
3.3.5權重因子的討論----------------------------------------24
3.4 邊緣對齊調變技術---------------------------------------25
3.4.1傳統脈衝寬度調變法------------------------------------26
3.4.2 偏移輸出方法-----------------------------------------28
3.4.3分散式邊緣對齊調變技術與集中式邊緣對齊調變技術--------29
3.4.4 邊緣對齊調製技術實現方法與空白時間-------------------39
第四章 機台實驗結果----------------------------------------41
4.1 簡介---------------------------------------------------41
4.2 權重控制實驗結果---------------------------------------43
4.2.1 零序注入與漏電流之關係-------------------------------43
4.2.2 調節命令與線性調變範圍之關係-------------------------46
4.2.3 權重控制策略-----------------------------------------50
4.2.4權重控制中性點電壓補償--------------------------------53
4.3邊緣對齊調變技術實驗結果--------------------------------55
4.3.1反向位配置與分散式邊緣對齊調變技術比較----------------55
4.3.2反向位配置與集中式邊緣對齊調變比較--------------------59
第五章 結論與未來展望--------------------------------------62
5.1結論----------------------------------------------------62
5.2未來展望------------------------------------------------63
參考文獻---------------------------------------------------64

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